US20180263665A1

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Info

Publication number: US20180263665A1
Application number: US15/982,587
Authority: US
Inventors: George Yacoub; Jeff Nichols
Original assignee: Globus Medical Inc
Current assignee: Globus Medical Inc
Priority date: 2011-07-15
Filing date: 2018-05-17
Publication date: 2018-09-20
Also published as: US20210322061A1; US11076887B2

Abstract

Orthopedic fixation devices and methods of installing the same. The orthopedic fixation device may include a coupling element and a bone fastener, whereby the bone fastener can be loaded into the coupling element through the bottom of a bore in the coupling element.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of U.S. patent application Ser. No. 14/849,736, filed on Sep. 10, 2015, which is a continuation-in-part of U.S. patent application Ser. No. 14/514,796, filed on Oct. 15, 2014, now U.S. Pat. No. 9,549,763, which is a divisional of U.S. patent application Ser. No. 13/183,965, filed on Jul. 15, 2011, now U.S. Pat. No. 8,888,827, the contents of which are incorporated by reference herein in their entireties for all purposes.

FIELD OF THE INVENTION

The present invention relates to orthopedic fixation devices, and, in one or more embodiments, to an orthopedic fixation device configured for loading of the bone fastener from the bottom of the tulip element.

BACKGROUND OF THE INVENTION

Many types of spinal irregularities can cause pain, limit range of motion, or injure the nervous system within the spinal column. These irregularities can result from, without limitation, trauma, tumor, disc degeneration, and disease. Often, these irregularities are treated by immobilizing a portion of the spine. This treatment typically involves affixing a plurality of fixation devices to one or more vertebrae and connecting the devices to an elongate rod that generally extends in the direction of the axis of the spine.

Treatment for these spinal irregularities often involves using a system of fixation devices to attain stability between spinal segments. Instability in the spine can create stress and strain on neurological elements, such as the spinal cord and nerve roots. In order to correct this, implants of certain stiffness can be implanted to restore the correct alignment and portion of the vertebral bodies. In many cases, a fixation device along with a vertical solid member can help restore spinal elements to a pain free situation, or at least may help reduce pain or prevent further injury to the spine.

Typically, fixation devices may include a bone fastener (e.g., bone screw, hook, etc.) for coupling the fixation device to vertebra. Fixation devices further may include a tulip element for coupling the bone fastener to the elongated rod. Clamp and/or wedge elements may be used to secure the bone fastener in the tulip element. A locking cap may be used to secure the rod in the tulip element. While these designs can be used in the treatment of spinal irregularities, they typically require loading of the bone fastener from the top of the tulip element. One drawback to this top-loading design is that different sizes of the tulip element must be used based on the diameter of the bone fastener to accommodate passage of the fastener through the tulip element, as the inner bore of the tulip element will generally need to be larger than either the combined size of the bone fastener head and clamp element or the bone fastener diameter. Another drawback to this top-loading design is that bone hooks cannot be used as they will generally not pass through the tulip element. Yet another drawback to this top-loading design is that bone fastener must be installed in the bone while attached to the tulip element.

Accordingly, there exists a need for new and improved orthopedic fixation devices.

SUMMARY OF THE INVENTION

In an exemplary embodiment, the present invention provides an orthopedic fixation device. The orthopedic fixation device may comprise a coupling element, the coupling element may comprise a bore there through and an interior surface disposed about the bore. The orthopedic fixation device further may comprise a bone fastener, wherein the bone fastener comprises a head and an extension that extends from the head, wherein the head is configured for loading into the coupling element through the bottom of the bore. The orthopedic fixation device further may comprise a locking clamp assembly. The locking clamp assembly may comprise a clamp element, wherein the clamp element comprises a first clamp portion and a second clamp portion, wherein the first and second clamp portions each have an outer surface and an inner surface, wherein at least a portion of the outer surface is configured to engage the interior surface of the coupling element, and wherein at least a portion of the inner surface is configured to engage the head of the bone fastener. The locking clamp assembly further may comprise a wedge element, wherein the wedge element comprises a wedge bore configured to receive an upper portion of the clamp element and an inner wedge surface disposed around at least a lower portion of the wedge bore, wherein the inner wedge surface is configured to engage at least portion of the outer surface of the first and second clamp portions.

In another exemplary embodiment, the orthopedic fixation device includes a coupling element, a bone fastener, and a locking clamp assembly. The coupling element comprises a bore extending therethrough and an interior surface disposed about the bore. The bone fastener comprises a head and an extension that extends from the head, wherein the head is configured for loading into the coupling element through the bottom of the bore. The locking clamp assembly comprises a clamp element and a wedge element. The clamp element has a spherical outer surface, a spherical inner surface, and a plurality of slits extending through the clamp element, wherein at least a portion of the outer surface is configured to engage the interior surface of the coupling element, and wherein at least a portion of the inner surface is configured to engage the head of the bone fastener. The wedge element comprises a wedge bore configured to receive an upper portion of the clamp element and an inner wedge surface disposed around at least a lower portion of the wedge bore, wherein the inner wedge surface is configured to engage at least a portion of the outer surface of the clamp element. The bone fastener is configured to angulate relative to the coupling element. In addition, the clamp element may be configured to angulate relative to the coupling element. This may allow the bone fastener to be angled up to 50 degrees relative to the coupling element.

Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred or exemplary embodiments of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein:

FIG. 1 is an exploded view of an orthopedic fixation device in accordance with embodiments of the present invention;

FIG. 2 is a perspective view of a locking clamp assembly in accordance with embodiments of the present invention;

FIG. 3 is a cross-sectional view of a locking clamp assembly in accordance with embodiments of the present invention;

FIG. 4 is a top view of a wedge element in accordance with embodiments of the present invention;

FIG. 5 is a side view of a wedge element in accordance with embodiments of the present invention;

FIG. 6 is a cross-sectional view of a locking clamp assembly disposed in a tulip element in an unlocked configuration in accordance with embodiments of the present invention;

FIG. 7 is a cross-sectional view of a locking clamp assembly disposed in a tulip element in a locked configuration in accordance with embodiments of the present invention;

FIG. 8 is a top view of a tulip element in accordance with embodiments of the present invention;

FIG. 9 is a top view of a locking cap assembly in accordance with embodiments of the present invention;

FIG. 10 is a perspective view of a locking cap assembly in accordance with embodiments of the present invention;

FIG. 11 is a cross-sectional view of a locking cap assembly in accordance with embodiments of the present invention;

FIGS. 12-14 illustrate an alternative orthopedic fixation device in accordance with embodiments of the present invention;

FIGS. 15-16 illustrate another alternative orthopedic fixation device in accordance with embodiments of the present invention;

FIGS. 17-19 illustrate yet another alternative orthopedic fixation device in accordance with embodiments of the present invention;

FIGS. 20-22 illustrate yet another alternative orthopedic fixation device in accordance with embodiments of the present invention;

FIG. 23 illustrates an orthopedic fixation device comprising a bone hook in accordance embodiments of the present invention;

FIGS. 24-25 illustrate an alternative wedge element in accordance with embodiments of the present invention;

FIG. 26 illustrates an offset iliac connector in accordance with embodiments of the present invention;

FIGS. 27-29 illustrate a bone fastener having a threaded instrument interface in accordance with embodiments of the present invention;

FIG. 30 illustrates a cross-sectional view of a vertebra having an orthopedic fixation device installed therein in accordance with embodiment of the present invention;

FIG. 31 is an exploded view of an orthopedic fixation device in accordance with embodiments of the present invention;

FIG. 32 is a perspective view of the orthopedic fixation device shown inFIG. 31, when assembled without the elongate rod;

FIG. 33 is a side view of the orthopedic fixation device shown inFIG. 31, when assembled without the elongate rod;

FIG. 34 is a cross-sectional view of the orthopedic fixation device shown inFIG. 31, when assembled without the elongate rod;

FIG. 35 is a cross-sectional view depicting angulation of the screw;

FIG. 36 is a cross-sectional view depicting angulation of the clamp and the screw;

FIG. 37 illustrates a cross-sectional view of an orthopedic fixation device in accordance with embodiments of the present invention;

FIGS. 38A and 38B illustrate side views of an orthopedic fixation device in accordance with embodiments of the present invention;

FIG. 39A illustrates a top view of a locking cap assembly in accordance with embodiments of the present invention;

FIGS. 39B and 39C illustrate side views of a locking cap assembly in accordance with embodiments of the present invention;

FIG. 40A illustrates an isometric view of a saddle in accordance with embodiments of the present invention;

FIG. 40B illustrates a cross-sectional view of the saddle ofFIG. 40A;

FIG. 41 illustrates an isometric view of a saddle in accordance with embodiments of the present invention;

FIG. 42A illustrates a top view of a retaining clip in accordance with embodiments of the present invention;

FIG. 42B illustrates a cross-sectional view of the retaining clip ofFIG. 41A;

FIG. 43 illustrates an isometric cross-sectional view of a tulip element and retaining clip in accordance with embodiments of the present invention;

FIG. 44 illustrates an orthopedic fixation device in accordance with embodiments of the present invention;

FIG. 45A illustrates an isometric exploded view of an orthopedic fixation device in accordance with embodiments of the present invention; and

FIG. 45B illustrates a cross-sectional view of the orthopedic fixation device ofFIG. 45A, as assembled.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Embodiments of the present invention are generally directed to orthopedic fixation devices configured for bottom loading of the bone fastener. Instead of loading the bone fastener from the top of the tulip element, embodiments of the present invention load the bone fastener from the bottom of the tulip element. With the bone fastener loaded in the tulip element, a locking clamp assembly can then be used to secure the bone fastener therein. Thus, unlike prior orthopedic fixation devices, embodiments of the present invention permit the use of larger bone fasteners without having to also increase the size of the tulip element. This should, for example, reduce the needed inventory, decreasing the necessary graphic cases needed to perform a similar procedure, while decreasing in-house inventory costs.

Further, as explained by the examples and illustrations below, the bone fastener of the orthopedic fixation devices can be placed in the vertebra without the tulip element in accordance with embodiments of the present invention. The tulip element can then be attached to the bone fastener in situ. This should reduce the material in the surgical wound, thus increasing visualization for disc preparation and interbody procedures, for example. The bone fastener can also be used to distract or otherwise manipulate the surgical site, further increasing visualization and ease of surgery, for example. Additionally, site preparation can be performed, in some embodiments, after the bone fastener has been placed, which may allow for more accurate pedicle decortication.

Turning now toFIG. 1, an exploded view of anorthopedic fixation device2 is illustrated in accordance with embodiments of the present invention. As illustrated, theorthopedic fixation device2 may comprise abone fastener4, a locking clamp assembly6 (which may comprise, for example, aclamp element7 and a wedge element8), atulip element10, and a lockingcap assembly12. As will be discussed in more detail below, thebone fastener4 may be loaded from the bottom of thetulip element10 with the lockingclamp assembly6 already loaded therein. Prior to being locked into place, thetulip element10 can be moved and rotated into a plurality of positions with respect to thebone fastener4. Once thetulip element10 is at the desired position with respect to thebone fastener4, thetulip element10 may be locked onto thebone fastener4. In the illustrated embodiment, the lockingcap assembly12 is configured to secure arod14 in thetulip element10. In one embodiment, thetulip element10 is fixed onto thebone fastener4 contemporaneously with securing of therod14 in thetulip element10.

As illustrated byFIG. 1, thebone fastener4 includes ahead16 and ashaft18 that extends from thehead16. The illustrated embodiment shows theshaft18 having a tapered shape andthreads20. Those of ordinary skill in the art will appreciate that theshaft18 may have a number of different features, such as thread pitch, shaft diameter to thread diameter, overall shaft shape, and the like, depending, for example, on the particular application. While thehead16 may have any general shape, at least a portion of thehead16 may have a curved surface in order to allow for rotational movement or angular adjustment of thebone fastener4 with respect to thetulip element10. For example, at least a portion of thehead16 may be shaped to form a portion of a ball or at least a portion of a sphere. As illustrated, thehead16 may have a roughened or texturedsurface22 that improves engagement with theclamp element7. In certain embodiments, thehead16 may have a tool engagement surface, for example, that can be engaged by a screw-driving tool or other device. The tool engagement surface can permit the physician to apply torsional or axial forces to thebone fastener4 to drive thebone fastener4 into the bone. In the illustrated embodiment, the tool engagement surface of thehead16 is apolygonal recess24. For instance, thepolygonal recess24 may be a hexagonal recess that receives a hexagonal tool, such as an allen wrench, for example. The present invention is intended to encompass tool engagement surfaces having other shapes, such as slot or cross that may be used, for example, with other types of screwdrivers. In an alternative embodiment (not illustrated), the engagement surface may be configured with a protruding engagement surface that may engage with a tool or device having a corresponding recess.

Referring now toFIGS. 1-3,clamp element7 of the lockingclamp assembly6 will be described in more detail in accordance with embodiments of the present invention. As illustrated, theclamp element7 includes afirst clamp portion26 and asecond clamp portion28. In the illustrated embodiment, thefirst clamp portion26 is substantially identical to and a mirror image of, thesecond clamp portion28. The first and

second clamp portions

26,28 provide a collar about thehead16 of thebone fastener4, when installed, as discussed in more detail below. The first and

second clamp portions

26,28

grip bone fastener

4 when force is applied onto theclamp element7 by thetulip element10. While the embodiments that are described and illustrated generally describe the first and

second clamp portions

26,28 as substantially identical, the

portions

26,28 may be of varying size and are not required to be mirror images of one another. In addition, while theclamp element7 is illustrated as having two clamp portions (first andsecond clamp portions26,28), theclamp element7 may comprise more than two portions for gripping thebone fastener4.

As illustrated, each of the first and

second clamp portions

26,28 includes an

outer surface

30,32, which may be curved or rounded, as best shown inFIGS. 1 and 2. The

outer surfaces

30,32 of the first and

second clamp portions

26,28 may each include an outer tapered

surface

34,36. In addition, the

outer surfaces

30,32 may each also have at least one slit38 formed therein. The at least one slit38 may, for example, allow the first and

second clamp portions

26,28 to constrict and securely engage thehead16 of thebone fastener4. The

outer surfaces

30,32 should abut and engage theinner wedge surface86 of thetulip element10 when fully installed and locked in place in thetulip element10 in accordance with present embodiments. With particular reference toFIG. 3, the first and

second clamp portions

26,28 each include

inner surfaces

38,40. When fully installed and locked in place in thetulip element10, the

inner surfaces

38,40 should abut and engage thehead16 of thebone fastener4 in accordance with present embodiments. The illustrated embodiment shows the

inner surfaces

38,40 having roughened ortextured features22 that improve engagement with thehead16 of thebone fastener4. The first and

second clamp portions

26,28 each may also include an

external lip

46,48, which may be located above the outer

tapered surfaces

34,36, as best seen inFIG. 3. The first and

second clamp portions

26,28 each may also include an

upper surface

31,33, as best seen inFIG. 1.

Referring now toFIGS. 1-5, thewedge element8 of the lockingclamp assembly6 will be described in more detail in accordance with embodiments of the present invention. As illustrated, thewedge element8 may include abore50. The lower portion of thebore50 may be sized to receive the upper portion of theclamp element7, including

external lips

46,48 of the first and

second clamp portions

26,28. The wedge element further may include anouter surface52 having a recessedportion54. Theouter surface52 may be generally rounded, for example. As best seen inFIG. 4, theouter surface52 of thewedge element8 may be generally elliptical, in one embodiment. The elliptical shape of theouter surface52 should, for example, limit radial motion of the wedge element when installed in thetulip element10. Thewedge element8 further may include anupper surface56. In the illustrated embodiment, theupper surface56 defines a seat that receives therod14. As illustrated, theupper surface56 may be generally convex in shape. In the illustrated embodiment, thewedge element8 further includes anupper lip57.

With particular reference toFIG. 3, thewedge element8 further includes aninner wedge surface58. As illustrated, theinner wedge surface58 may be disposed around a lower portion of thebore50. In one embodiment, theinner wedge surface58 forms a conical wedge. Theinner wedge surface58 operates, for example, to engage the outer

tapered surfaces

34,36 of the first and

second clamp portions

26,28 to force theclamp element7 down thebore62 of thetulip element10. Thewedge element8 further may include an inner protrudingsurface60 adjacent to theinner wedge surface58 and an inner recessedsurface62 adjacent the inner protrudingsurface60. Thewedge element8 further may include aninner seat64. As illustrated, theinner seat64 may be downwardly facing for receiving

upper surfaces

31,33 of the first and

second clamp portions

26,28. In an embodiment, theinner seat64 restricts or limits movement of theclamp element4 through thebore50 of thewedge element8.

In accordance with present embodiments, the lockingclamp assembly6 can be assembled prior to insertion into thetulip element10. In one embodiment, for assembly, theclamp element7 may be inserted into thewedge element8 upwardly through thebore50. The

outer surfaces

30,32 of the first and

second clamp portions

26,28 should slidingly engage theinner wedge surface58 of thewedge element8 as theclamp element7 is inserted. Theclamp element7 should be inserted until the

external lips

46,48 of the first and

second clamp portions

26,28 pass the inner protrudingsurface60 of thewedge element8. The inner protrudingsurface60 engages the

external lips

46,48 to secure theclamp element7 in thewedge element8. In the illustrated embodiment, the lockingclamp assembly6 will not fit downwardly through the top of thebore62 of thetulip element10 as the locking clamp assembly has an outer diameter at its biggest point that is larger than the inner diameter of the upper portion of thebore62.

Referring now toFIGS. 1 and 6-8, thetulip element10 will be described in more detail in accordance with embodiments of the present invention. As illustrated, thetulip element10 may comprise bore62, abody65 andarms66 that extend upwardly from thebody65. In the illustrated embodiment, thearms66 define aU-shaped channel68 sized to receive therod14. Each of thearms66 has aninterior surface70 theinterior surface70 having a threadedportion72 for engaging corresponding threads on a screw-driving tool (e.g.,tool144 onFIGS. 27-29). Theinterior surface70 of each of thearms66 further may include aslot74 for receiving corresponding tabs96 (e.g.,FIG. 9) of the lockingcap assembly12 and a recessedsurface76 for engaging corresponding protuberances100 (e.g.,FIG. 9) of the lockingcap assembly12. As illustrated, the recessedsurface76 of each of thearms66 may be located above theslot74. Theinterior surface70 of each of thearms66 further may include aprotuberance78. In the illustrated embodiment, theprotuberance78 of each of thearms66 is located below the threadedportion72 with the threadedportion72 being located between theprotuberance78 and theslot74. As best seen inFIG. 6, theinterior surface70 of each of thearms66 further may form a downwardly facingseat79, for example, which may limit or restrict movement of the lockingclamp assembly6 through thebore62. Each of thearms66 further may include anouter surface80. Theouter surface80 of each of thearms66 may include atool engagement groove82 formed on theouter surface80 which may used for holding thetulip element10 with a suitable tool (not illustrated).

As illustrated, thebody65 of thetulip element10 may have anouter surface84, which may be curved or rounded, as best seen inFIG. 1. With particular reference toFIGS. 6 and 7, thebody65 further may include aninner wedge surface86 disposed around a lower portion of thebore62. In one embodiment, theinner wedge surface86 forms a conical wedge. Theinner wedge surface86 of thebody65 of thetulip element10, for example, may abut and engage the

outer surfaces

30,32 of the first and

second clamp portions

26,28 when the lockingclamp assembly6 is fully installed and locked in place.

In accordance with present embodiments, the lockingclamp assembly6 may be installed in thetulip element10 in either an unlocked position or a locked position.FIG. 6 illustrates the lockingclamp assembly6 disposed in thetulip element10 in the unlocked position in accordance with embodiments of the present invention. InFIG. 6, the lockingclamp assembly6 has been inserted into thetulip element10 upwardly through thebore62. The lockingassembly6 should be inserted until theupper lip57 of thewedge element8 passes theprotuberances78 located on theinterior surfaces70 of thearms66 of thetulip element10. Theprotuberances78 should engage theupper lip57 to secure the lockingclamp assembly6 in thetulip element10. While not illustrated onFIG. 6, the bone fastener4 (e.g., shown onFIG. 1) can now be placed into the lockingassembly6 through a snap fit with theclamp element7. There should be sufficient clearance for theclamp element7 to expand and snap around thehead16 of thebone fastener4. The lockingclamp assembly6 and thetulip element10, however, should still be free to rotate with respect to thebone fastener4. Thetulip element10 can be moved and rotated to obtain a desired portion with respect to thebone fastener4. The lockingclamp assembly6 should also move with the tulip element during rotation of thetulip element10 with respect to thebone fastener4. Once thetulip element10 is at the desired position, thetulip element10 may be locked onto thebone fastener4. The lockingclamp assembly6 and thetulip element10 should cooperate to lock theclamp assembly6 onto thehead16 of thebone fastener4.

FIG. 7 illustrates the lockingclamp assembly6 disposed in thetulip element10 in the locked position in accordance with embodiments of the present invention. InFIG. 7, the lockingclamp assembly6 has been pushed downwardly in thebore62 of thetulip element10. As illustrated, the lockingclamp assembly6 has been pushed downward until theupper lip57 of thewedge element8 passes theprotuberances78 located on theinterior surfaces70 of thearms66 of thetulip element10. As the lockingclamp assembly6 moves downward, theclamp element7 engages thebody65 of thetulip element10. As illustrated, the

outer surfaces

30,32 of the first and

second clamp portions

26,28 of theclamp element7 should abut and engage theinner wedge surface86 of thebody65 of thetulip element10, forcing

inner surfaces

38,40 of the first and

second clamp portions

26,28 to engagehead16 of the bone fastener4 (e.g.,FIG. 1). In the locked position,tulip element10 should be locked onto thebone fastener4, thus preventing further positioning of thetulip element10 with respect to thebone fastener4.

Referring now toFIGS. 1 and 9-11, the lockingcap assembly12 will be described in more detail in accordance with embodiments of the present invention. As illustrated, the lockingcap assembly12 may comprise abody88 and aset screw90 threaded into abore92 in thebody88. Theset screw90 may have a length, for example, that is longer than the length of thebore92. In the illustrated embodiment, at least a portion of theset screw90 extends from the top of thebody88. In certain embodiments, theset screw90 may have a tool engagement surface, for example, that can be engaged by a screw-driving tool or other device. The tool engagement surface can permit the physician to apply torsional or axial forces to theset screw90 to advance theset screw90 through thebody88 and onto therod14. When the lockingcap assembly12 is in its locked position, theset screw90 can be advanced through thebody88 to engage therod14, applying downward force onto therod14 and securing it to thetulip element12. In one embodiment, theset screw90 forces therod14 downward and into contact with the lockingclamp assembly6 causing the lockingcap assembly6 to move downward in thetulip element10. In the illustrated embodiment, the tool engagement surface of theset screw90 is apolygonal recess94. For instance, thepolygonal recess94 may be a hexagonal recess that receives a hexagonal tool, such as an allen wrench, for example. The present invention is intended to encompass tool engagement surfaces having other shapes, such as slot or cross that may be used, for example, with other types of screwdrivers. In an alternative embodiment (not illustrated), the engagement surface may be configured with a protruding engagement surface that may engage with a tool or device having a corresponding recess.

In accordance with present embodiments, thebody88 may have one or more projections. For example, thebody88 may compriselower tabs96 projecting radially from a lower end of thebody88. In the illustrated embodiment, thebody88 comprises a pair oflower tabs96 located on opposite sides of thebody88. As illustrated, thelower tabs96 may each have anouter surface98 that is generally rounded in shape. In addition, while thebody88 is illustrated as having twolower tabs96, thebody88 may comprise more than twolower tabs96. As illustrated, thebody88 further may compriseprotuberances100. Theprotuberances100 may engage with corresponding recessed surface76 (e.g.,FIG. 10) of thearms66 of thetulip element10. Theprotuberances100 may be capable of providing a tactile or audible signal to the physician, such as a click that may be felt or heard, when the lockingcap assembly12 has reached its locking position. Theprotuberances100 also may assist in maintaining the lockingcap assembly12 in its locked position. In the illustrated embodiment, thebody88 further may comprise tool engagement features. The tool engagement features may, for example, be used for holding or manipulating the lockingcap assembly12 with a suitable tool (not illustrated). In the illustrated embodiment, the lockingcap assembly12 includesupper tabs102. As illustrated, thetabs102 may be formed at the upper surface of thebody88. In the illustrated embodiment, the lockingcap assembly12 includes fourupper tabs102 at the corners of the upper surface. In addition, while thebody88 is illustrated as having fourupper tabs102, thebody88 may comprise more or less than fourupper tabs102.

outer surfaces

30,32 of the first and

second clamp portions

inner surfaces

38,40 of the first and

second clamp portions

26,28 to engagehead16 of thebone fastener4 and secure it with respect to thetulip element10.

Referring now toFIGS. 12-14, locking of thetulip element10 onto thebone fastener4 is illustrated in more detail in accordance with embodiments of the present invention. For the purposes of this illustration, the locking cap element12 (e.g.,FIG. 1) is not shown. Thetulip element10 shown inFIGS. 12-14 is similar to thetulip element10 described previously except that thetulip element10 does not include a threaded portion72 (e.g.,FIGS. 6-7) or a downwardly facing seat79 (e.g.,FIG. 6) in theinterior surface70 of thearms66 of thetulip element10.FIG. 12 illustrates the lockingclamp assembly6 installed in thetulip element10 in an unlocked position. As previously mentioned, the lockingclamp assembly6 can be inserted into thetulip element10 upwardly through thebore62. As shown inFIG. 12, the lockingassembly6 should be inserted until theupper lip57 of thewedge element8 passes theprotuberances78 located on theinterior surfaces70 of thetulip element10. Theprotuberances78 should engage theupper lip57 to secure the lockingclamp assembly6 in thetulip element10. As illustrated byFIG. 13, thebone fastener4 can now be placed into the lockingassembly6 through a snap fit with theclamp element7. There should be sufficient clearance for theclamp element7 to expand and snap around thehead16 of thebone fastener4. The lockingclamp assembly6 and thetulip element10, however, should still be free to rotate with respect to thebone fastener4. Thetulip element10 can be moved and rotated to obtain a desired portion with respect to thebone fastener4. Once thetulip element10 is at the desired position, thetulip element10 may be locked onto thebone fastener4. The lockingclamp assembly6 and thetulip element10 should cooperate to lock theclamp assembly6 onto thehead16 of thebone fastener4.

FIG. 14 illustrates the lockingclamp assembly6 disposed in thetulip element10 in the locked position and clamping onto thebone fastener4 to secure thebone fastener4 with respect to thetulip element10 in accordance with embodiments of the present invention. As seen inFIG. 14, the lockingclamp assembly6 has been pushed downwardly in thebore62 of thetulip element10 until theupper lip57 of thewedge element8 passes theprotuberances78 located on theinterior surfaces70 of thearms66 of thetulip element10. As the lockingclamp assembly6 moves downward, theclamp element7 engages thebody65 of thetulip element10 such that the

outer surfaces

30,32 of the first and

second clamp portions

inner surfaces

38,40 of the first and

second clamp portions

26,28 to engagehead16 of thebone fastener4. In the locked position,tulip element10 should be locked onto thebone fastener4, thus preventing further positioning of thetulip element10 with respect to thebone fastener4.

Referring now toFIGS. 15 and 16, anorthopedic fixation device2 is described in accordance with alternative embodiments of the present invention. As illustrated, theorthopedic fixation device2 comprises abone fastener4, lockingclamp assembly6, and atulip element10. For the purposes of this illustration, the locking cap assembly12 (e.g.,FIG. 1) is not shown. As previously mentioned, the lockingclamp assembly6 comprises aclamp element7 and awedge element8. As illustrated, theclamp element7 may include afirst clamp portion26 and asecond clamp portion28. In the illustrated embodiment, the first and

second clamp portions

26,28 each include an inner

tapered surface

106,108 such that the lower portions of the first and

second clamp portions

26,28 can expand when pressure is applied that constricts the upper portion of the first and

second clamp portions

26,28. In contrast, to thewedge element8 that was previously described, embodiments of theupper surface56 of thewedge element8 illustrated onFIGS. 15 and 16 do not define a seat that receives the rod14 (e.g.,FIG. 1), but rather are generally planar withbore50 penetrating there through. As illustrated, thewedge element8 further includes aninner wedge surface58 formed around a lower portion of thebore50. As also previously mentioned, thetulip element10 generally may comprise abore62,base64, andarms66. The inner diameter of thebore62 in the upper portion of thetulip element10 may be made smaller than either the combined size of theclamp element7 and thebone fastener4 or the diameter of theshaft14 of thebone fastener4, whichever is larger. As illustrated, thearms66 may each comprise aninterior surface70. In the illustrated embodiment, theinterior surface70 includes inner taperedsurface104 rather than a downwardly facing seat79 (e.g.,FIG. 6) in theinterior surface70 of thearms66 of thetulip element10.

With continued reference toFIGS. 15 and 16, locking of thetulip element10 onto thebone fastener4 will be described in more detail in accordance with embodiments of the present invention. The first and

second clamp portions

26,28 of theclamp element7 may be inserted one after another upwardly into thebore62 of thetulip element10. The first and

second clamp portions

26,28 may be pushed axially towards the top of thetulip element10. The first and

second clamp portions

26,28 should continue to move upwardly until they engage the inner taperedsurface104 of thetulip element10. Due the taper angle of the inner taperedsurface104, the upper portion of the first and

second clamp portions

26,28 will be forced to move inwards until the inner tapered

surfaces

106,108 of each of the first and

second clamp portions

26,28 come into contact. This contraction at the top of the first and

second clamp portions

26,28 should result in a wider opening at the bottom of theclamp element7. Thebone fastener4 can then be inserted through the bottom of thebore62 of thetulip element10 and into theclamp element7. Thebone fastener4 can then be manipulated, for example, to center theclamp element7 into thehead16 of thebone fastener4. Thetulip element10, however, should still be free to rotate with respect to thebone fastener4. Thetulip element10 can be moved and rotated to obtain a desired portion with respect to thebone fastener4. Once thetulip element10 is at the desired position, thetulip element10 may be locked onto thebone fastener4.

To lock thetulip element10, thebone fastener4 can be pulled downward and because theclamp element7 is in engagement with thebone fastener4, theclamp element7 should also move downward in thetulip element10 such that theclamp element7 engages thebody65 of thetulip element10. As illustrated, the

outer surfaces

30,32 of the first and

second clamp portions

inner surfaces

38,40 of the first and

second clamp portions

26,28 to clamp onto thehead16 of thebone fastener4. Thewedge element8 can then be introduced downwardly from the top of thebore62 in thetulip element10 to seat on top of theclamp element7. Thewedge element8 should engage theinterior surfaces70 of thetulip element10 preventing upward movement of theclamp element7, locking theclamp element7 in its engagement with thehead16 of the bone fastener. In the locked position, thetulip element10 should be locked onto thebone fastener4, thus preventing further positioning of thetulip element10 with respect to thebone fastener4.

Referring now toFIGS. 17-19, anorthopedic fixation device2 is described in accordance with alternative embodiments of the present invention. As illustrated, theorthopedic fixation device2 comprises abone fastener4, a lockingclamp assembly6, and atulip element10. For the purposes of this illustration, the locking cap assembly12 (e.g.,FIG. 1) is not shown. In the illustrated embodiment, the lockingclamp assembly6 comprises aclamp element7 and awedge element8. Theorthopedic fixation device2 is similar to the embodiments ofFIGS. 15-16 except that embodiments of thewedge element8 include downwardly extendingtabs110 that fits into correspondingslots112 in the top of thehead16 of thebone fastener4. In general, thetabs110 should impart a uni-planar restraint on thebone fastener4 so that it only slides along mating surfaces. The interior surfaces114 of thetabs110, best seen inFIG. 19, should forms the sides of the internal driving features. In an alternative embodiment (not illustrated), thewedge element8 can be configured so that thetabs110 are interconnected, for example, to impart more strength to the design of thewedge element8.

Referring now toFIGS. 20-21, anorthopedic fixation device2 is described in accordance with alternative embodiments of the present invention. As illustrated, theorthopedic fixation device2 comprises abone fastener4, a lockingclamp assembly6, and atulip element10. For the purposes of this illustration, the locking cap assembly12 (e.g.,FIG. 1) is not shown. In the illustrated embodiment, the lockingclamp assembly6 comprises aclamp element7 and awedge element8.

Theorthopedic fixation device2 is similar to the embodiments ofFIGS. 15-16 except that embodiments of theclamp element7 are configured for top loading from the top of thebore62 in thetulip element10. Instead of being inserted upwardly from the bottom of thebore62, the first and

second clamp portions

26,28 of theclamp element7 are inserted downwardly from the top of thebore62, until the

clamp portions

26,28 engage theinner wedge surface86 of thebody65 of thetulip element10. Thebone fastener4 can then be inserted upwardly from the bottom of thebore62 of thetulip element10 and into engagement with theclamp element7 whereby theclamp element7 will be pushed upwardly towards the top of thetulip element10. Theclamp element7 will move higher until they engage an external temporary stop (not illustrated) that prevents further upward movement. As theclamp element7 moves higher in thetulip element10, the

clamp portions

26,28 adjust and reorient due to increased clearance with theinner wedge surface86 of thetulip element10 such that the opening at the bottom of theclamp element7 is larger than the diameter of thehead16 of thebone fastener4.

To lock thetulip element10, thebone fastener4 can be pulled downward and because theclamp element7 is in engagement with thebone fastener4, the clamp element should also move downward in thetulip element10 such that the

outer surfaces

30,32 of the first and

second clamp portions

inner surfaces

38,40 of the first and

second clamp portions

26,28 to clamp onto thehead16 of thebone fastener4. In accordance with present embodiments, the smallest inner diameter for thebore62 in thetulip element10 is smaller than the combined size of theclamp element7 and thehead16 of thebone fastener4, when in engagement. Thewedge element8 can then be introduced downwardly from the top of thebore62 in thetulip element10 to seat on top of theclamp element7. Thewedge element8 should engage theinterior surfaces70 of thetulip element10 preventing upward movement of theclamp element7, locking theclamp element7 in its engagement with thehead16 of the bone fastener. In the locked position, thetulip element10 should be locked onto thebone fastener4, thus preventing further positioning of thetulip element10 with respect to thebone fastener4.

Referring now toFIG. 22, anorthopedic fixation device2 is described in accordance with alternative embodiments of the present invention. As illustrated, theorthopedic fixation device2 comprises a lockingclamp assembly6 and atulip element10. For the purposes of this illustration, the bone fastener (e.g.,FIG. 1) and locking cap assembly12 (e.g.,FIG. 1) are not shown. In the illustrated embodiment, the lockingclamp assembly6 comprises aclamp element7 and awedge element8.

Theorthopedic fixation device2 is similar to the embodiments ofFIGS. 20-21 except that embodiments of thewedge element8 include a retention feature for coupling with theclamp element7. As illustrated, thewedge element8 includes an inner protrudingsurface60 that engages with the

external lips

46,48 of the first and

second clamp portions

26,28 of theclamp element7 to secure theclamp element7 in thewedge element8. The lockingclamp assembly6 with theclamp element7 secured in thewedge element8 can then be inserted downwardly from the top of thebore62 in thetulip element10, until the

clamp portions

26,28 engage theinner wedge surface86 of thebody65 of thetulip element10. Once thebone fastener4 is snapped into theclamp element7, the lockingclamp assembly6 can be forced downwards through thetulip element10 into its locked position to secure the bone fastener (e.g.,FIG. 1) in theclamp element7. In the locked position, thetulip element10 should be locked onto thebone fastener4, thus preventing further positioning of thetulip element10 with respect to thebone fastener4.

While the embodiments that are described and illustrated above generally illustrate abone fastener4 in shape of a screw having ahead16 andshaft18 extending there from, it should be understood that other bone fasteners may also be used such as hooks and sacral blocks. Thus, the present invention may be used with a wide variety of bone fasteners in addition to a bone screw, as described above. For example,FIG. 23 illustrates an embodiment in which thebone fastener14 includes ahead16 having an extension in the form of ahook116 that extends from thehead16. In the illustrated embodiment, thehead16 is secured in thetulip element10 by theclamp element7 and thewedge element8. As illustrated, thehead16 may have a roughened or texturedsurface22 that improves engagement with theclamp element7.

FIGS. 24 and 25 illustrate awedge element8 having an optional rod retention feature, in accordance with embodiments of the present invention. In some embodiments, the rod retention feature of thewedge element8 may be added to enhance retainment of the rod14 (e.g.,FIG. 1) in a surgical procedure. In the illustrated embodiment, the rod retention feature is in the form ofseat extensions118 that will cradle therod14 to retain it in thewedge element8. As illustrated, thewedge element8 comprises anupper surface56 defining a seat for receiving therod14. Thewedge element8 further may compriseseat extensions118 for retaining the rod in thewedge element8. In one embodiment, theseat extensions118 may be configured to flex when arod14 is pushed down throughopening122 at the top of theseat extensions118. When pressed down, therod14 may engage the ends of theseat extensions118 causing theseat extensions118 to flex outward increasing the size of the opening so that therod14 can be moved downwards to rest on theupper surface56 of thewedge element8. In other words, therod14 may be snapped past theseat extensions118 in accordance with some embodiments. In the illustrated embodiment, thewedge element8 further includesnotches122 to facilitate flexing of theseat extensions118.

While the embodiments that are described and illustrated above generally illustrate atulip element10 in the general shape of a “U” for coupling therod14 to thebone fastener4, it should be understood that any of a variety of different coupling elements may be used in accordance with embodiments of the present invention. For example, the coupling element may be open (e.g.,tulip element10 onFIG. 1) or closed. In some embodiments, therod14 may be top loaded into an open coupling element. In other embodiments, therod14 may be side loaded, for example, into a closed coupling element. In some embodiments, the coupling element may be an open, closed, or offset iliac connector. In yet other embodiments, the coupling element may be a posted screw connector. In addition, the coupling element may be configured to move polyaxially, monoaxially, or uni-planar with respect to thebone fastener4 prior to locking of the coupling element onto thebone fastener4.

As previously illustrated and described with respect toFIG. 1, thetulip element10 may include a threadedportion72.FIGS. 27-29 illustrate the threadedportion72 of thetulip element10 in more detail. As illustrated, thetulip element10 includes abody65 andarms66. As best seen inFIG. 28, thearms66 each include aninterior surface70 having a threadedportion72. In accordance with present embodiments, abone fastener4 can be secured to thetulip element10. As illustrated, atool144, which may be, for example, a screw-driving tool, can be placed through thebore62 in thetulip element10 and into engagement with thetulip element10 and thebone fastener4. In the illustrated embodiment, thetool144 includes a threadedportion146 that engages the threadedportion72 of thetulip element10. Thetool144 further includes anengagement end148 below the threadedportion72 that engages with the polygonal recess24 (e.g., hexagonal) in thehead16 of thebone fastener4. In this manner, a rigid connection may be formed between thebone fastener4 and thetool144.

FIG. 30 illustrates installation of theorthopedic fixation device2 in avertebra150 in accordance with embodiments of the present invention. As illustrated, thebone fastener4 may be implanted into thevertebra150. Thebone fastener4 may then be secured to thetulip element10 using, for example, the lockingclamp assembly6. Thetulip element10 can then be moved and rotated into a desired position with respect to thebone fastener4 and then locked onto thebone fastener4. In one embodiment, thetulip element10 is fixed onto thebone fastener4 contemporaneously with securing therod14 to thetulip element10 with the lockingcap assembly12. In this manner, therod14 can be secured in a fixed position relative to thevertebra150.

Turning now toFIGS. 31-36, an alternative embodiment oforthopedic fixation device202 is illustrated.FIG. 31 provides an exploded view of theorthopedic fixation device202. As illustrated, theorthopedic fixation device202 may comprise abone fastener204, a lockingclamp assembly206 includingclamp element207 andwedge element208, atulip element210,elongate rod214, and threaded lockingcap212. This embodiment may be particularly suitable for posterior cervical or posterior cervico-thoraco constructs due to the increased angulation of thetulip element210 relative to thebone fastener204. In this embodiment, up to 100 degrees of conical angulation of thebone fastener204 relative to thetulip element210 may be obtained. Thebone fastener204 may be loaded from the bottom of thetulip element210 with the lockingclamp assembly206 already loaded therein. Prior to being locked into place, thetulip element210 can be freely moved and rotated into a plurality of positions with respect to thebone fastener204.

Thebone fastener204 includes ahead216 and a threadedshaft218 that extends from thehead216. In this embodiment, thehead216 is substantially smooth and is shaped to form a portion of a ball or at least a portion of a sphere. The threadedshaft218 has a blunt tip and a compound taper. Two thread cutting flutes may be provided for self-tapping. Thescrew head216 may include adriving recess224 as described elsewhere herein, e.g., a hexalobular recess, for screw insertion.

Thetulip element210, similar totulip element10, may be sized and configured to receiveelongate rod214 therein. For example, thetulip element210 may be sized to receive a 3.5 mm or 4.0 mm diameter rod. As best seen inFIG. 34, an interior surface of thetulip element210 may have a threadedportion272 for engagingcorresponding threads290 on the threadedlocking cap212. Thus, the threadedlocking cap212 may be secured directly to thetulip element210, for example, by rotating thelocking cap212 into a top portion of thetulip element210 and engagingthreads272. As best seen inFIG. 33, one ormore indentations282, such as chevron type indentations, may be provided on an outer surface of thetulip element210 for attachment of reduction instruments or the like (not illustrated).

Thewedge element208 includes an upper surface that defines a seat configured to receive therod214 and a lower surface that is configured to contact and receive theclamp element207. Thewedge element208 is captured by an elliptical profile inner diameter of thetulip element210. This profile keys thewedge element208 to a specific orientation to thetulip element210. A v-notch in the upper surface of thewedge element208 may allow for therod214 to have at least two points of contact, thereby adding stability to the assembly when locked. A spherical diameter of thewedge element208 contacts a spherical diameter on theclamp element207 and retains theclamp element207 in thetulip element210. As thelocking cap212 is tightened down, therod214 will apply pressure to thewedge element208 to lock theclamp element207 andbone fastener204 in position.

By using spherical interfacing contact surfaces, a higher degree of angulation can be achieved. As shown inFIG. 35, thebone fastener204 may be angled relative to theclamp member207 andtulip element210, respectively. In particular, thebone fastener204 may be angled relative to a longitudinal axis of thetulip element210. For example, up to ±41 degrees of angulation (82° total) may occur between theclamp element207 and thebone fastener204. InFIG. 35, there is no clamp angulation (i.e., zero degrees) such that a longitudinal axis of theclamp member207 extends along the same longitudinal axis as thetulip element210. A greater degree of angulation can be achieved by also angling theclamp member207 relative to thetulip element210. For example, up to ±9 degrees of angulation (18° total) may occur between theclamp element207 and thetulip element210. As shown inFIG. 36, thebone fastener204 is angled relative to theclamp member207 and theclamp member207 is angled relative to thetulip element210. Therefore, when combined, a total of up to ±50 degrees of angulation (100° total) in any direction may occur between thetulip element210 and thebone fastener204. This greater degree of conical angulation of thebone fastener204 provides more versatility and options especially in rod constructions positioned in difficult or small spaces.

Once thetulip element210 is at the desired position with respect to thebone fastener204, thetulip element210 may be locked onto thebone fastener204. In the illustrated embodiment, the lockingcap212 is of a threaded type having an external threadedportion290 extending from a first end to a second end of thelocking cap212. The lockingcap212 may also be provided with a recess, such as a hexalobular driving recess, for engagement with a driving instrument (not shown). The threadedlocking cap212 is configured to directly secure therod214 in thetulip element210. Thus, the threadedlocking cap212, when secured to thetulip element210, locks thescrew204 to therod214 and locks thebone fastener204 into position, thereby fixing the degree of angulation of thebone fastener204 relative to thetulip element210.

Referring now toFIG. 37, anorthopedic fixation device300 is described in accordance with alternative embodiments of the present invention. Theorthopedic fixation device300 is substantially similar to theorthopedic fixation device2 discussed above. As such, a description of similar elements and features will be omitted here for clarity. As illustrated, theorthopedic fixation device300 comprises a bone fastener4 (only thehead314 of the fastener is shown), a lockingclamp assembly305 having asaddle306 and aretaining clip307, atulip element310, and a lockingcap assembly312. In the illustrated embodiment, thesaddle306 includes a sphericallower surface303 for receiving thehead314 of thebone fastener4 and a curvedupper surface309 for receiving a rod (i.e.,rod14 discussed above). Thesaddle306 is inserted into thetulip element310 from the bottom until inwardly protrudingshoulders308 of an inner surface of thetulip element310 engage corresponding engagement features311, which are formed in anouter surface301 of thesaddle306. As a result, thesaddle306 is locked in place during initial installation of thesaddle306 in thetulip element310. Subsequently, thehead314 of thebone fastener4 is inserted into thetulip element310 from the bottom so that thehead314 is disposed beneath thesaddle306. To prevent thebone fastener4 from falling out of thetulip element310, the retainingclip307 is inserted into anannular channel316 formed in a distal portion of aninner wall318 of thetulip element310. Finally, thesaddle306 is pushed downward to overcome the engagement of the engagement features311 with theshoulders308 so that thesaddle306 limits axial movement of thebone fastener4. As will be discussed below, an inner diameter of the retainingclip307 is less than a maximum diameter of thehead314 of thebone fastener4. As such, axial movement of the largest portion of thehead314 beyond the retainingclip307 is prevented.

Theorthopedic fixation device300 may be configured to accommodate various-sized rods (e.g., rod14). To provide such variability, the spacing betweenarms366 of thetulip element310 and aset screw390 of the lockingcap assembly312 are configured to accommodate various-sized rods including, for example, rods having a diameter of about 5.5 mm and about 6.0 mm.FIG. 38A illustrates thefixation device2 with arod14A having a first diameter (e.g., 5.5 mm).FIG. 38B illustrates thefixation device2 with a rod14B having a second diameter larger than the first diameter (e.g., 6.0 mm). Theset screw390 may be turned so that the male threads of theset screw390 and the female threads in thebody388 of the lockingcap assembly312 engage to advance theset screw390 further into thetulip element310 until theset screw390 contacts therod14A or14B. Subsequently, theset screw390 is advanced further downward to exert a downward force on therod14, which in turn exerts a downward force on the saddle306 (not shown inFIGS. 38A, 38B) below therod14. As theset screw390 is advanced further downward, the force exerted on thesaddle306 moves thesaddle306 downward, thus exerting a downward force on thehead314 of thebone fastener4. Theset screw390 may be advanced far enough such that thehead314 is wedged between thesaddle306 and the retainingclip307, as shown inFIG. 37.

FIGS. 39A-39C illustrate the lockingcap assembly312 in accordance with embodiments of the present invention. The lockingcap assembly312 is similar to the lockingcap assembly12. As such, a description of similar elements or features will be omitted here for clarity. Similar to the lockingcap assembly12, thebody388 of the lockingcap assembly312 may include a pair oftabs496 extending from opposite sides of thebody388. In some embodiments, a radially outermost surface of eachtab496 may include aflat portion402, as shown more clearly inFIG. 39A. In such embodiments, a slot374 (similar to theslot74 discussed above) formed in the interior surface of thearms366 of thetulip element310 may include corresponding flat surfaces302 (shown inFIG. 37). Theflat portions402 advantageously ensure correct positioning and locking in place of thebody388 when the lockingcap assembly312 is installed. As shown more clearly inFIG. 39B, in some embodiments, thetabs496 may additionally include a positivelead angle405 to advantageously reduce splay of thearms366 during turning of thebody388 to lock thecap assembly312 in thetulip element310.

FIGS. 40A and 40B illustrate isometric and cross-sectional views, respectively, of thesaddle306 discussed above. As illustrated, thesaddle306 is similar to thewedge element8 discussed above except that abore320 extending through thesaddle306 includes alower portion322 that is sized and shaped to receive at least a portion of thehead314 of the bone fastener4 (as similarly depicted in the embodiments ofFIG. 42). As noted above, in some embodiments, the outer surface324 of thesaddle306 includes engagement features311 disposed on opposite sides of thesaddle306 and configured to engage the inwardly protrudingshoulders308 of thetulip element310 to lock thesaddle306 in place during initial installation of thesaddle306 in thetulip element310. After insertion of thebone fastener4 and the retainingclip307 into thetulip element310, thesaddle306 is pushed downward to overcome the engagement of the inwardly protrudingshoulders308 with the engagement features311 to maintain appropriate clearance between the lockingcap assembly312 and therod14 when the lockingcap assembly312 is assembled during a surgical procedure. The engagement features311 also serve to advantageously prevent upward axial motion of thesaddle306 after it has been moved into contact with thehead314.

In some embodiments, the engagement features311 may include at least one protrusion404 extending radially outward from thesaddle306 and at least onerecess408 adjacent the protrusion404. Therecess408 is configured to receive theshoulder308 of thetulip element310. The protrusion404 is configured to abut against theshoulder308 after thesaddle306 has been pushed below theshoulder308 to limit axial movement of thesaddle306 after thefastener4 has been installed. In some embodiments, thesaddle306 may include at least two elliptical axial

cross-sectional portions

410A and410B to advantageously prevent rotation of thesaddle306 relative to and within thetulip element310. In some embodiments, the first elliptical axialcross-sectional portion410A extends perpendicularly to the second elliptical axialcross-sectional portion410B, as illustrated inFIG. 40A. In some embodiments, a lower portion of the saddle306 (e.g., the area of the saddle around the lower portion322) may have an elliptical axial cross-section in the axial direction to advantageously provide additional support for the prevention of the rotation of thesaddle306 within thetulip element310. In some embodiments, the lower portion of thesaddle306 may alternatively have a circular cross-section in the axial direction.

FIG. 41 depicts asaddle406 in accordance with alternative embodiments of the present invention. Thesaddle406 is substantially similar to thesaddle306 described above. As such a description of similar elements and features will be omitted here for clarity. In some embodiments, thesaddle406 may include a pair of engagement features411 (one visible inFIG. 41) disposed on opposite sides of thesaddle406. Similar to the engagement features311, eachengagement feature411 includes at least oneprotrusion414 and at least one recess418. However, in the embodiment illustrated inFIG. 41, eachengagement feature411 may additionally include at least oneflat surface409 which interfaces with a corresponding flat surface (not shown) formed in the inner surface of the tulip element to advantageously prevent rotation of thesaddle406 within the tulip element.

FIG. 43 illustrates atulip element510 and aretaining clip507 of an orthopedic fixation device in accordance with embodiments of the present invention. Thetulip element510 is substantially similar to the

tulip elements

10 and310 discussed above. As such, a description of similar elements and features is omitted here for clarity. In the embodiment ofFIG. 43, thetulip element510 includes a firstangled surface519A disposed in a distal portion of thetulip element510 above anannular channel516 into which theretaining clip507 is inserted. The retainingclip507 includes a secondangled surface519B, which together with the firstangled surface519A, provides a locking taper to retain the head of a bone fastener (e.g.,bone fastener4, not shown inFIG. 43). In some embodiments, thetulip element510 and the retainingclip507 may be used in conjunction with a locking clamp assembly such as, for example, the lockingclamp assembly6. As the locking clamp assembly is pushed downward by the locking cap and rod, the clamp portions of the locking clamp assembly are forced radially inward, thus gripping the head of the bone fastener and locking the polyaxial motion of the bone fastener. In some embodiments, the upper and lower surfaces of the retainingclip507 include a plurality of hills and valleys, as illustrated inFIG. 43, to advantageously lock theretaining clip507 in place and prevent it from moving within thetulip element510.

FIG. 44 illustrates anorthopedic fixation device600 in accordance with embodiments of the present invention. Theorthopedic fixation device600 is substantially similar to theorthopedic fixation device300 discussed above, except that theorthopedic fixation device600 includes (a) atulip element610 having an interior surface that is threaded and (b) a threadedlocking cap612. As illustrated inFIG. 44, the interior surface of thetulip element610 may have a threadedportion672 for engagingcorresponding threads690 of the threadedlocking cap612. Thus, the threadedlocking cap612 may be secured directly to thetulip element610, for example, by rotating the threadedlocking cap612 into an upper portion of thetulip element610, thus engaging thethreads672. As illustrated inFIG. 44, in some embodiments, the threaded engagement of the threadedlocking cap612 and the upper portion of thetulip element610 may include a positive angle at the top angle of the threadedportion672 and leading angles of the threads690 (i.e., lower surfaces of thethreads690 of the threadedlocking cap612 and upper surfaces of threads of the threadedportion672 of thecoupling element610 slope downward and outward). As a result, the threadedlocking cap612 is more securely held in place and splaying of the arms of thetulip element610 is substantially reduced or eliminated. Theorthopedic fixation device600 also includes asaddle606, which is substantially similar to the saddle506 discussed above. However, in some embodiments, and as illustrated inFIG. 44, the flat portions and protrusions discussed above with respect to thesaddle306 may be omitted. In some embodiments, however, thesaddle606 may alternatively include such flat portions and protrusions. In addition, in some embodiments, the upper portion of thesaddle606 may have an elliptical cross-section when viewed in the axial direction. Similar to the saddle506, the elliptical cross-section of the upper portion of thesaddle606 limits rotation of thesaddle606 within the tulip element. In the embodiment ofFIG. 44, thesaddle606 may be inserted from the top of the tulip element and rotated into place. As a result, the more robust engagement of thesaddle606 with the tulip element is achieved, assembly is simplified, and a hard stop is provided to limit upward movement of thesaddle606.

FIG. 45A depicts an isometric exploded view of anorthopedic fixation device700 in accordance with embodiments of the present invention.FIG. 45B depicts a cross-sectional view of theorthopedic fixation device700, as assembled. Theorthopedic fixation device700 is substantially similar to theorthopedic fixation device300 discussed above. As such, a description of similar elements and features will be omitted here for clarity. Theorthopedic fixation device700 includes alocking cap712, atulip element710, abone fastener704 having ahead714, a retainingclip707, and asaddle706. Similar to theorthopedic fixation device300, the lockingcap712 is inserted into thetulip element710 and rotated 90° to lock it into thetulip element710. In some embodiments, the lockingcap712 may include a plurality of protrusions790 which are disposed in a corresponding plurality ofrecesses772 formed in an inner surface of the tulip element790 to ensure that the lockingcap712 is securely locked in place. In some embodiments, the lockingcap712 may further include a downwardly protrudingbump720. Thebump720 advantageously allows for a downward force on arod14 and thesaddle706 without requiring thelocking cap712 to have threads. As a result, polyaxial motion of thebone fastener704 can either be locked (when thelocking cap712 is rotated into position within the tulip element710) or allowed (when thelocking cap712 is not rotated into position) without the necessity of repeatedly turning the locking cap712 (as required when the locking cap includes threads).

The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims. Although individual embodiments are discussed herein, the invention covers all combinations of all those embodiments.

Claims

What is claimed is:

1. An orthopedic fixation device comprising:

a coupling element having a bore extending therethrough, an interior surface disposed about the bore, and an annular channel formed in a distal portion of the interior surface;

a bone fastener, wherein the bone fastener comprises a head and an extension that extends from the head, wherein the head is configured for loading into the coupling element through the bottom of the bore;

a locking cap assembly, wherein the locking clamp assembly comprises:

a body having a bore extending through the body and a pair of tabs extending from opposite sides of the body, wherein the bore includes a threaded portion, and wherein a radially outermost surface of each tab includes a flat portion; and

a set screw extending through the bore of the body and having threads corresponding to the threaded portion of the bore of the body;

a saddle having a bore extending through the saddle, wherein the saddle includes a lower portion sized and shaped to receive at least a portion of the head of the bone fastener; and

a retaining clip disposed below the fastener in the annular channel of the coupling element, wherein an inner diameter of the retaining clip is less than a maximum diameter of the head of the bone fastener.

2. The orthopedic fixation device ofclaim 1, wherein a lower portion of the saddle has an elliptical cross-section in the axial direction.

3. The orthopedic fixation device ofclaim 1, wherein the retaining clip is annular and includes an opening disposed through a thickness of the retaining clip.

4. The orthopedic fixation device ofclaim 3, wherein an inner surface of the retaining clip is angled.

5. The orthopedic fixation device ofclaim 1, wherein the saddle comprises engagement features disposed on opposite sides of an outer surface of the saddle and configured to engage inwardly protruding shoulders of the coupling element.

6. The orthopedic fixation device ofclaim 5, wherein the engagement features are protrusions.

7. The orthopedic fixation device ofclaim 1, wherein the saddle further comprises at least two elliptical axial cross-sectional portions configured to prevent the saddle from rotating relative to and within the coupling element.

8. The orthopedic fixation device ofclaim 1, wherein the saddle further comprises a first elliptical cross-sectional portion and a second elliptical cross-sectional portion extending perpendicular to the first elliptical cross-sectional portion.

9. The orthopedic fixation device ofclaim 1, wherein the coupling element is a tulip element having a plurality of arms configured to receive an elongate rod.

10. An orthopedic fixation device comprising:

a tulip element, wherein the tulip element comprises a bore extending therethrough, an interior surface disposed about the bore, an annular channel formed in a distal portion of the interior surface, and a plurality of arms configured to receive an elongate rod;

a bone fastener, wherein the bone fastener comprises a head and an extension that extends from the head, wherein the head is configured for loading into the tulip element through the bottom of the bore;

a locking cap assembly, wherein the locking clamp assembly comprises:

a saddle comprising:

a bore extending through the saddle;

a lower portion sized and shaped to receive at least a portion of the head of the bone fastener;

engagement features disposed on opposite sides of an outer surface of the saddle and configured to engage inwardly protruding shoulders of the tulip element; and

at least two elliptical cross-sectional portions; and

a retaining clip disposed below the fastener in the annular channel of the tulip element, wherein an inner diameter of the retaining clip is less than a maximum diameter of the head of the bone fastener.

11. The orthopedic fixation device ofclaim 10, wherein a lower portion of the saddle has an elliptical cross-section in the axial direction.

12. The orthopedic fixation device ofclaim 10, wherein the retaining clip is annular and includes an opening disposed through a thickness of the retaining clip.

13. The orthopedic fixation device ofclaim 12, wherein an inner surface of the retaining clip is angled.

14. An orthopedic fixation device comprising:

a threaded locking cap having threads that engage a corresponding threaded portion of the coupling element, wherein lower surfaces of the threads of the threaded locking cap and upper surfaces of threads of the threaded portion of the coupling element slope downward and outward;